Lifting-jack



C; W. RIPSCH AND J. C. DAWLEY.-

' LIFTING JACK.

APPLICATION FILED AUG.16, 1920.

Patented May 3,1921

2 SHEEYTSSHEET I.

IN V EN TORS (l/111F1 5 wlP/PJCH A TTRNEY C. W. RIPSCH AND J. 'C. DAWLEY.

LIFTING JACK.

APPLICATION FILED AUGJS, 1920- 1, 7 31 Patented May 3,1921.

7 2 SHEE TSSHEET 2.

UNITED stares earner oer ca f CHARLES WM. RIPSCH AND JAMES DAWLEY, OF DAY'ION, OHIO.

Lamina-JACK.

Specification of Letters Patent.

, Patented May 3, 1 921.

Application filed August 16, 1920. Serial No. 403,818.

To all whom it may concern:

Be it known that we, CHARLES W.Rirsorr and JAMns C. DAWLEY, citizens of the United States, residing at Dayton, in the county of Montgomeryand State of Ohio, have invented certain new and useful Improvements in Lifting-Jacks, of which the following is a specification, reference being had .therein to the. accompanying drawing.

This invention relates to lifting jacks and more particularly to a liftingjaok of the self lowering type. 1 I

The object of the "invention is to provide a practical, highly efficient, self lowerin jack which will be motor operated. V

A further object of the invention is to provide such a jack in which the load may be lowered independently of the motor.

A further object of the invention is to provide such a jack'in which the motor must be disconnected from the liftingele-v ment before the load can'be lowered.

Other objects of the invention will appear as the device is described in detail.

In the accompanying drawings Figure 1 is a side elevation, partly in section, of a ack embodying our 1nvent1on; Fig. 2 1s a plan view, partly broken away, of such a jack; Fig. 3 is a side elevation, partly broken away, ofsuoh a jack; and Fig. 4 is a detail view, partly in section, of the clutch and brake operating device.

. In these drawings we have illustrated one embodiment of our invention and have shown the same as applied to a self lowering jack, the main features of construction and operation of which are well known,.but it will be understood that this particular embodiment of the invention has been chosen for the purpose of illustration only and that the invention may take various forms and thereto an upwardly extending hollow 12 rigidly secured to the housing 2 in which is mounted a vertically movable lifting member 3. This lifting member is here shown as a hollow standard havlng at its upper end a cap, or load engaglng member, 4 and having at its lower enda nut 5 into which is threaded an actuat ng screw 6 the lower end of which is rotatably supported on the base 1. This screw isrotated to impart upward movement to the lifting element by means of an operating shaft 7 which is journaled in partitions 8 and 9 in a lateral extension 10 of;

the housing The operating shaftmay be connected with the screw in any suitable manner but, as here shown, a'beveled gear 11 is rigidly securedto the lower end of the screw andmeshes with a beveled gear inner end of the operating shaft 7.

The operating shaft is driven from a motor of any suitable kind but preferably we employ an electric motor, as shown at 13.

The motor may be connected with the operating shaftin any suitablemanner but we.

J: V PI'GLGI' to employ worm gearingas this glves the necessary reduction in. speed and is very powerful in 1ts operation. As here shown, a worm gear 14 is mounted on the,

operating shaft and meshes with a worm 15 rlgldly secured toa'shaft 16 with which the shaft of the motor 13 is directly conbe disconnected from the lifting element during the lowering of the load and to .this end a clutch may be interposed between the motor and the lifting element. lVhile this clutch may be located at any suitable point we have, in the present construction, arranged it between the worm wheel 14 and the shaft 7 Tothis end the worm wheel 14 is rotatably mounted on the shaft 7 and'has secured thereto one member 17 of the clutch, the other member 18 of which is slidably mounted on the shaft 7 and is held against rotation thereon. trolled in any suitable manner but preferably the member 18 is positively moved into and out of operative engagement with the member 17 thereof and to this end the clutch member 18 is provided with a circumferential groove 19 into which extend pins 2O carried by a yoke 21 mounted on a shaft 22.

The pitchof the screw 6 which actuates the lifting element is such that when unre- The clutch maybe connected. It is desirable that the motor should 2 strained, the liftingelement will move downwardly under the Weight of its load.

7 These controlling devices are here shown as of such a character that they will'be connected with the lifting element only during its downward movement and they preferably comprise a worm wheel 23 loosely mounted on the shaft 7 and adapted to be automatically connected therewith when said shaft is rotated in a reverse direction by the down ward movement of the lifting element. To this end the worm wheel carries one member 24 of a clutch, the other member 25 of which is slidably mountedon the shaft 7, held against rotation relatively thereto, and pressed toward the first mentioned clutch member 24 by means of springs, oneof which is shown at 26. The clutch members are provided with ratchet teeth so that when the shaft is rotated in a forward direction,

that is the direction in which. it is rotated to lift the load, the teethof the clutch member 25 ride over the teeth of the clutch member 24; and if the shaft 7 is rotated in the opposite direction the teeth of the clutch members will be brought into operative engagement to rigidly connect the worm wheel to the shaft. The worm gear 23 meshes with a worm 27 rotatably mounted on a shaft 28' extending at right angles to the shaft '7 and the pitch of the spirals of the worm and suitable device for controlling the thereof, which is preferably in the form of a brake.

worm gear is such that the worm will be rotated by the worm wheel. Connected with the worm 27 for rotation therewith, and preferably mounted on the shaft 28, is

' a second worm wheel 29 which meshes with a second worm 30 rigidly secured to a shaft .31, the pitch of the spirals on the worm gear 29 and the worm 30 being also such that the worm will be rotated by the worm gear.

rotation Inasmuch as the worm gearing will absorb, to a very large degree, the power, or thrust, exerted upon the shaft 7 by the downward movement of the. load, a very light braking action will serve to con trol the movement of the worm 30 and, coin sequently, of the load. As here shown, the

brake comprises a drum 32 rigidly secured to the shaft '31 and adapted to be rotated at a relatively high speed by that shaft, due to the speed multiplying action of the worm gearing. (Cooperating with the bralre drum are two brake shoes 33 which are provided the arms 84 and to thus move the brake shoes out of engagement with the, brake drum and to release the load. As here shown, this Connected. with the worm 30 is a is accomplished by inserting between the ends of the arms 34 a cam shaped operating member 36 which is carried by, and preferably formed integral with, a stud 37 jourarms 34 against the tension of the spring 35.

It is desirable that the motor should be disconnected from the operating shaft before the latter isrotated in a reverse direc-. tion by the downward movement of the load, and the present construction is such that the motor must be disconnected from the shaft before theload can begin its downward movement. To accomplish this we have provided a single actuating device for operating the clutch, 17- 18, and the cam 36 and the construction is such that :the clutch will be actuated to disconnect the motor before thebrake is manipulated to release the load. In the present construction this is accomplished by providing the stud 37,- which carries the cam 36, withca rock arm 39 which is connected by a link 40 with the yoke 21 of the clutch, so, that this clutch will be actuated upon each operation of the lever 38. To cause-the'clut'ch to be operated before the brake is released the cam 35 is of such a character that there will be sufficient clearance; between ,the same and the arms 84 of the brake topermit the clutch to be disengaged before the camoperatively engages the. arms. :As shown an fulllines in Fig. 4, thecam is out of engagement with the brake arms 34, its fiat s des being spaced appreciable distances from J the respective arms. As shownin dotted lines the cam has been rotated a sufficient'distance to -"cause the clutch 1718 to be operated toldisconnect the motor from the shaft and the cam has just engaged the arms 34, so that the further movement thereof will separate these arms and release the brake.

The operation of the mechanism will be readily understood from the foregoing description of the several parts thereof and it will be apparent that we have provided 2 a lifting ack in which the lifting element is elevated by power derived from a motor and in which the lifting element and its load may be lowered by gravity independently of the motor, the motor being discon-- nected from the lifting el ment during the lowering operation. It will further be apparent that we have provided means for con trolling the downward movement of the load, independently of the motor, and that this means is of such a character that its manipulation to permit the downward move-,,

ment of the load will cause the motor to be disconnected from the lifting element be;

fore the latter begins its downward movemer t. F t W ll be app that well adapted to the handlingof heavy loads for which the jack is designed, jacks of this t pe being designed for loads up'-"to fifty and seventy-five tons.

IVhile wehave shownand described-none embodiment of our invention we wish'itito be understood that we do not desire to be limited to the details thereof as various modifications may occur'to a person skilled in the art. A V ff 7,.

Having now fully described our invention what we claim as new and desire to secure by Letters Patent is: r

1. In a lifting jack, a lifting element, a motor operatively connected with said lifting element, means for disconnecting said motor from said'lifting element to permit the latter to move downwardly independently of the motor, and means for controlling the downward movement of said lifting element.

2. Ina lifting jack, a lifting element, a motor operatively connected with said lifting element, devices to control the downward movement of said lifting element, said devices comprising a brake and means for disconnecting said motor from said lifting element and for manipulating said brake.

3. In a lifting jack, a lifting element, a motor operatively connected with said lifting element, devices to control the downward movement of said lifting element, said devices comprising means to hold said lifting element normally against downward movement, and a single operating member for disconnecting said motor from said lifting element and for releasing said load to permit it to move downwardly.

4. In a lifting jack, a lifting element, a

, motor operatively connected with said lifting element, devices to control the downward movement of said lifting element, said devices comprising means to hold the load normally against downward movement, and means to cause said motor to be disconnected from said lifting element before said controlling devices may be actuated to release the lifting element for downward movement.

5. In a lifting jack, a lifting element, a motor operatively connected with said'lifting element, devices to control the downward movement of said lifting element, said devices comprising a normally operative brake, and means to cause said motor to be disconnected from said lifting element before said brake is manipulated to permit the downward movement of said lifting element. 7

6. In a lifting jack, a lifting element, a

motor operatively connected with said lifting element, devices to control the downward movement of said lifting element,

said" devices comprising; a brake, and a a single operating'member for disconnecting I said motor from said lifting element and for manipulating said brake.

17-.xIn", a lifting jack, a lifting. element, amotor, a clutch toxoperatively connect said motor with said lifting element, devices to control thedownward; movement; of said lifting element, said devices "comprising means to hold saidliftingelement normally against downward movement and; an op-;

erating member operatively connected with, said clutch and with said holding means.

8. In a lifting jack, a lifting element, a motor, a clutch to operatively connect said motor with said lifting element, devices to control the downward movement of said lifting element, said devices comprising a normally operative brake, means to release said brake, and an operating member vconnected with said releasing means and with said clutch.

9. In a lifting jack, a lifting element, a motor, a clutch to operatively connect said motor with said lifting element, devices to control the downward movement of said lifting element, said devices comprising a normally operative brake, and a device operatively connected with said brake and with said clutch, said connections being such that said clutch will be operatedbefore said brake is operated.

10. In a lifting jack, a lifting element,,a

-motor, a clutch to operatively connect said motor with said lifting element, devices to control the downward movement of said lifting element, said devices comprising a normally operative brake, an actuating device for said clutch, and a lost motion connection between said actuating device and said brake, whereby the manipulation of said device will first shift the clutch and then release the brake.

11. In a lifting jack, a lifting element, a a

motor, a clutch to operatively connect said motor with said lifting element, devices to control the downward movement of said. lifting element, said devices comprising a brake drum, brake shoes cooperating with said drum and having intersecting arms, a spring tending to move said arms one toward the other, a rotatable cam arranged between said arms, I means for actuating said cam to separate said'arms, and an operative connection between said actuating means and said clutch.

12. In a lifting jack, a lifting element, a motor, a clutch to operatively connect said motor with said lifting element, devices to control the downward movement of said lifting element, said devices comprising a brake drum, brake shoes coeperating with said drum and having intersecting arms, a spring tending to move said arms onetoward the other, a rotatable stud mounted adjacent to said arms, a cam shaped member carried by said stud and arranged between said arms with its contact surfaces normally out of engagement with the re spectivearms, a connection between said stud and said'clutch, and means for rotating said stud. V

13. In a lifting jack, a lifting element, a shaft to operatively connect said lifting element, a motor, a clutch to operatively connect said motor with said shaft, a worm gear rotatably mounted on said shaft,

means for connecting said worm gear with said shaft when the latter rotates in a reverse direction, a worm meshing with said worm gear and adapted to be rotated thereby, a brake connected with said worm, an

actuating device for said brake, and an operative connection between said actuating device and said clutch.

In testimony whereof, we affix our signa tures hereto.

CHARLES WM. RIPSCH. JAMES C. DAWLEY. 

